Mobile phone users usually store phone numbers in their contact lists using the most common format for their countries. In the U.S. such a format could be something like 650-555-0000 (area code and phone number) and, in Brazil, it could be something like 041 31 9999-9999 (carrier code+area code+phone number). Note that even corresponding parts of phone numbers may have different formats in different countries. For example, U.S. numbers use three digit area codes and seven digit phone numbers, while Brazilian numbers use two digit area codes and eight digit phone numbers. Also, certain countries use types of phone number information that are not used universally. For example, Brazilian dialing requires a carrier code, which is not generally required when dialing in the U.S.
This system of differing phone number formats may be acceptable for domestic travel, where only one format of phone number is used consistently. For example, a resident of Brazil who remains in Brazil can format dialed numbers in the Brazilian fashion and, similarly, store phonebook numbers according to the Brazilian standard.
However, if a U.S. resident travels to another country, such as Brazil, a problem results. Most likely, the U.S. resident's phonebook will store entries in the U.S. format. Similarly the U.S. resident will be familiar with dialing phone numbers in the U.S. format. Since the U.S. resident will be dialing from Brazil, the phone number in the U.S. format will be introduced to the Brazilian telecommunications network, and the dialing process will fail.
There are some programs and some implementations in specific mobile phones that include carrier codes for countries that use them, or otherwise provide limited location-based reformatting. However, these attempts at a solution to the location-based phone number formatting problem do not possess the capability of automatically determining an appropriate format for a location and transforming a dialed number into a predetermined format so that it can be easily and transparently dialed in that format.